Motor advanced spring charging pawl and ratchet mechanism with spring assist

ABSTRACT

A circuit breaker operating mechanism characterized by a crank shaft, a closing spring connected to the crank shaft, motoroperating structure for driving the crank shaft to charge the closing spring, a ratchet wheel mounted on the crank shaft, a reciprocating pawl structure supported to drive the ratchet wheel, a motor comprising an output shaft and cam means or driving means on the output shaft operable upon each revolution of the output shaft to operate the pawl structure to advance the ratchet wheel to thereby charge the closing spring, the cam means being operable in directions toward and away from the reciprocating pawl structure, and spring means attached to the output shaft for urging the reciprocating pawl structure only in the direction of advancement of the ratchet wheel.

United States Patent Davies Nov. 20, 1973 SPRING ASSIST [75] Inventor: Norman Davies, Trafford, Pa.

[73] Assignee: Westinghouse Electric (Zorporation,

Pittsburgh, Pa.

[22] Filed: Oct. 27, 1972 [21] Appl. No.: 301,690

[52] US. Cl. 200/1153 SC, 185/40 R, 335/76 [51] Int. Cl llltllh 3/30, F03g 1/08 [58] Field of Search 200/153 SC, 153 P'; 185/40 R, 40 A, 40 B; 74/575, 577 R, 577 S, 149; 335/68, 76, 77; 310/75 R, 75 A [56] References Cited UNITED STATES PATENTS 3,176,796 4/1965 Fredrickson 185/40 R 3,600,540 8/1971 Bould 200/153 SC FOREIGN PATENTS OR APPLICATIONS 1,191,751 10/1959 France 74/575 N 39 El fi rJ l1 I Primary Examiner-Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye Attorney-A. T. Stratton et al.

[57] ABSTRACT A circuit breaker operating mechanism characterized by a crank shaft, a closing spring connected to the crank shaft, motor-operating structure for driving the crank shaft to charge the closing spring, a ratchet wheel mounted on the crank shaft, a reciprocating pawl structure supported to drive the ratchet wheel, a motor comprising an output shaft and cam means or driving means on the output shaft operable upon each revolution of the output shaft to operate the pawl structure to advance the ratchet wheel to thereby charge the closing spring, the cam means being operable in directions toward and away from the reciprocating pawl structure, and spring means attached to the output shaft for urging the reciprocating pawl structure only in the direction of advancement of the ratchet wheel.

PAIENIEDnnvzo 1913 3773395 SHEET 30F 6 PAIENIEDMUV 20 I975 SHEU 5 BF 6 Pmmnnuuvzo ma 3773.995

sum 6 CF 0 FIG. 7

MOTOR ADVANCED SPRING CHARGING PAWL AND RATCHET MECHANISM WITH SPRING ASSIST BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a motor operated spring closing circuit breaker and more particularly it pertains to means for increasing the charging torque of the ratchet mechanism therefor.

2. Description of the Prior Art Most of the circuit breaker operating mechanisms of recent construction employ a ratchet wheel and pawl as part of the closing spring charging mechanism. For example, in U.S. Pat. No. 3,585,330 to Fred Bould, issued June 15, 1971, a motor operated reciprocating member moves the pawl to turn the ratchet wheel one notch for each rotation of the motor. With the increasing demand for electrical power and consequently higher short circuit requirements, circuit breakers have required more powerful closing springs with a consequent need for higher torque charging motors with a resulting added cost to the circuit breakers.

SUMMARY OF THE INVENTION It has been found in accordance with this invention that the foregoing problem may be satisfied by providing a circuit breaker comprising cooperating contacts, a crank shaft having a closing spring operatively connected thereto,.a ratchet wheel on the crank shaft rotatable therewith, a reciprocating member having a pawl thereon which is supported to operate the pawl to advance the ratchet wheel upon reciprocation thereof, a motor comprising an output shaft, cam means on the output shaft operable upon rotation of the output shaft to operate the reciprocating member to advance the ratchet wheel to thereby charge the closing spring, the cam means being operable in directions toward and away from the reciprocating member, and spring means attached to one of the reciprocating members and the output shaft for urging the member only in the direction toward the ratchet wheel.

The advantage of the device of this invention is the provision of means for increasing the charging torque of a ratcheting mechanism without increasing the size of the motor; or, in the alternative, providing a smaller inexpensive motor where a particular charging torque is required.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view, with parts broken away, of a multi-pole circuit breaker constructed in accordance with the principles of this invention;

FIG. 2 is a side sectional view, on an enlarged scale relative to FIG. 1, and with parts broken away, illustrating part of the operating mechanism of the circuit breaker of FIG. 1;

FIG. 3 is a side sectional view, with parts broken away, illus trating the closing cam and linkages of the mechanism seen in FIG. 2;

FIG. 4 is a side sectional view, with parts broken away and on an enlarged scale relative to FIG. 2, of the motor-operating structure for operating the crank shaft to charge the closing spring seen in FIG. 2;

FIG. 4a is an alternative embodiment of the structure shown in FIG. 4 using a compression spring instead of a tension spring;

FIG. 5 is a top view, with parts broken away, of the motor-operating mechanism seen in FIG. 4 with the closing cam shown on the crank shaft;

FIG. 6 is a sectional view, with parts broken away, taken generally along the line VIVI of FIG. 4;

FIG. 7 is a side view of another embodiment wherein the drive shaft of the motor is perpendicular to the axis of rotation of the ratchet wheel;

FIG. 8 is a side view of another embodiment of the invention; and

FIG. 9 is a graph of force required vs. crank movement through 180 produced by a motor with and without the aid of a torque spring.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, there is shown, in FIG. 1, a circuit breaker 5 comprising a supporting frame 7 mounted on wheels or rollers 9. The circuit breaker 5 is a three-pole circuit breaker comprising a stationary contact 11 and a movable contact 13 cooperating with the stationary contact 11. The movable contact 13 is supported on a contact arm 15 that is pivoted on a pin 17 and driven by means of an elongated rod structure 19 that is pivotally connected to the contact arm 15 at 21. The elongated rod structure 19 is pivotally con nected to a lever 23 that is fixedly supported on a jack shaft 25 (FIGS. 2 and 3) that is supported for rotation about an axis normal to the paper as seen in FIGS. 2 and 3. The jack shaft 25 is common to all three poles of the circuit breaker and rotatable to simultaneously move the movable contacts 13 of the three poles between open and closed positions. The circuit breaker 5 is a roll-out or drawout metal-clad type circuit breaker having a general construction that is well known in the art.

The circuit breaker 5 comprises an internal supporting frame structure 27 (FIGS. 2 and 3) comprising a pair of spaced frame members 29. The jack shaft 25 is supported on suitable bearings on the frame members 29. A hexagonal shaped crank shaft 31 is supported on suitable bearings on the frame members 29 for rotational movement about the elongated axis thereof which is normal to the plane of the paper as seen in FIGS. 2 and 3. A closing cam 33 (FIG. 3) is fixedly secured to the crank shaft 31. In addition to the closing cam 33, a ratchet wheel 35 and a crank arm 37 are each fixedly secured to the crank shaft 31. A reciprocating member 39 (FIG. 4) mounted on the crank shaft 31 for movement relative to the crank shaft 31 about the axis of the crank shaft 31, and a reciprocating memher 41 is mounted on the crank shaft 31 for movement relative to the crank shaft 31 about the axis of the crank shaft 31. The operation of the member 39 and 41 will be hereinafter more fully described.

The crank arm 37 (FIG. 2) comprises a first leg 43 having a roller 45 mounted thereon and a second leg 47 having a pin 49 thereon that extends through an opening in an elongated rod 51. The rod 51 extends through a coil closing spring 53 and is connected to a springretaining plate 55 at the one end thereof. The spring 53, at the left-hand (FIG. 2) end thereof, engages the supporting frame structure 27.

The operating mechanism comprises a tripping latch assembly 59 (FIG. 3), a toggle linkage 61, and a closing latch assembly 63 (FIG. 2). The tripping latch assembly 59, toggle linkage 61, closing latch assembly 63, closing cam 33, and closing-spring 53, along with the operations thereof, comprise the type more specifically described in the above-mentioned US. Pat. No. 3,254,186. Thus, only a brief description of the construction and operation of those parts is provided herein.

The operating mechanism is shown in FIGS. 2 and 3 in the contact-closed position with the closing spring 53 in the spring-charged position. The closing spring 53 is latched in the spring-charged position by a latch member 67 that is pivotally supported on the frame 29 by means of a pin 69 and that engages the roller 45 of the crank-arm 37. A trigger latch 71 engages a roller 73 supported on the latch member 67 to latch the latch member 67. The circuit breaker is latched in the contact-closed position against the bias of an opening spring 75 by the trippinglatch assembly 59 (FIG. 3). The toggle linkage 61 comprises a toggle link 77 and a toggle link 79 pivotally connected together by a knee pivot having a roller 81 thereon. The toggle link 77 is pivotally connected to the lever 23 by means of a pin 83 and the toggle link 79 is pivotally connected to a latch member 85 by means of a pin 87. The latch member 85 is supported for pivotal movement on a pin 89. The latch member 85 is latched against counterclockwise (FIG. 3) movement by means of a latch member 91 pivotally supported intermediate the ends thereof on a pin 93. As can be seen in FIG. 3, the latch member 91 is provided with a separate roller at each of the opposite ends thereof. The latch member 91 at one end thereof engages the latch 85 to prevent counterclockwise movement of the latch 85, and the latch member 91 is engaged by a trigger latch 97, pivotally supported on a pin 99, that latches the latch member 91 in latching position.

When it is desired to open the circuit breaker, the tripping latch 97 may be rotated in a clockwise (FIG. 3) direction about the pin 99. This movement releases the latch member 91 which can then move counterclockwise about the pin 93 to release the latch 85. The latch 85 is then free to move counterclockwise about the pin 89 to thereby permit the toggle link 79 to move to the right with the roller 81 moving off of the high surface of the cam 33. The opening spring 75 then operates to rotate the lever 23 and jack shaft 25 in a clockwise (FIG. 3) direction to permit movement of the rods 19 (FIG. 1) downward to cause counterclockwise movement of the contact arms about their associated pivots 17 to the open position. During the tripping movement, a resetting spring 103 (FIG. 3) pulls the toggle 61 to move the roller 18 into the notch portion of the cam 33. The circuit breaker may then be closed by release of the closing latch assembly 63 (FIG. 2).

The circuit breaker is closed by pivoting the closing latch 71 in a clockwise (FIG. 2) direction about the pin 72 to enable the latch member 67 to rotate counterand jack shaft 25 in a counterclockwise direction to thereby move the rods 19 (FIG. 1) upward to pivot the contact arms 59, about their respective pivots 17, to the closed position seen in FIG. 1.

The closing spring 53 may then be charged by operating the ratchet wheel 35 in a counterclockwise direction in a manner to be hereinafter more specifically described. Upon rotation of the ratchet wheel 35 in a counterclockwise direction, the rod 51 is pulled to the left to pull the plate 55 to the left (FIG. 2) to compress the closing spring 53 during the first half of a 360 revolution of the crank shaft 31. As the pin 49, to which the arm 51 is connected, passes over center, the closing spring 53, which is fully charged at that point, expands slightly moving the crank shaft 31 in a counterclockwise direction, and the closing latch 67 engages the roller 45 to again latch the spring 53 and the crank shaft 31 in the spring-charged position seen in FIG. 2. In this position, the roller 81 (FIG. 3) is maintained on the high point of the closing cam 33 to maintain the contacts in the closed position.

Means are provided for operating the ratchet wheel 35 to move the crank shaft 31 in order to charge the closing spring 53. A motor-operating mechanism 109 (FIG. 4) comprises a supporting frame 111 having a motor 113 fixedly supported thereon with the axis of the output shaft 115 of the motor extending in a direction that is normal to the axis of the crank shaft 31. The axis of the output shaft 115 is normal to a plane in which the axis of the crank shaft 31 is disposed. The axis of the crank shaft 31 (FIG. 2) is normal to the planes of the spaced parallel planar supporting plates 29 and the axis of the motor output shaft is parallel to the planes of the supporting plates 29. In FIGS. 4 and 5, an operating arm 119, having a roller 121 on the free end thereof, is fixedly secured to the output shaft 115 to rotate with the output shaft 1 15. The operating arm 119 and roller 121 serve as cam means or driving means for driving the reciprocating member 39. A

plate 125 is fixedly secured to the reciprocating member 39 by bolt means 127. The plate 125 is provided with an arcuate bottom surface 129 that is engaged by the roller 121. A spring 131 is provided to bias the reciprocating member 39 downward, which downward movement is limited by the engagement of the reciprocating member 39 with the roller 121. A pawl 139 is pivotally mounted on the reciprocating member 39 by means of apin 141 and biased in a counterclockwise (FIG. 4) direction by means of a torsion spring 143. The reciprocating member 39 is mounted on a bearing member 147 that is fixed to the hexagonal crank shaft 31 with the reciprocating member 39 being pivotally movable against a surface 148 of the bearing 147 relative to the crank shaft 31.

A handle-operating reciprocating member 41 is also mounted on the bearing 147 for reciprocal pivotal movement on the bearing relative to the crank shaft 31. A pawl 149 is pivotally mounted on the reciprocating member 41 by means of a pin 151 and biased in a counterclockwise (FIG. 4) direction by means of a torsion spring 153. The ratchet wheel 35 is provided with missing-tooth portion 155 that is adjacent to the pawl 139 when the closing spring is fully charged so that continued operation of the motor 113 after the spring is fully charged will not apply damaging forces to the parts of the circuit breaker. Thus, the motor can over-run past the spring-charged position of the crank shaft 31 until the motor slows to a stop position. A tension spring 159 is connected between a stationary part 161 of the circuit breaker frame and the reciprocating member 41 to bias the reciprocating member 41 in a clockwise (FIG. 4) direction into engagement with a stop surface 163 on the stationary part 161.

The ratchet wheel 35 may be manually operated by manual reciprocation of the reciprocating member 41 during which movement the pawl 149 serves as the drivingpawl with the pawl 139 serving as the holding pawl. The member 41 is provided with a pocket at the end thereof for receiving a handle-extension that can be inserted into the pocket to permit a manual cranking operation of the reciprocating member 41.

The parts are shown in FIGS. 24 in the contact closed position with the closing spring 53 in the charged position. In that position, the pawl 139 is adjacent the missing-tooth portion 155 of the ratchet wheel 35 so that as the motor 113 slows to a stopped position after the spring is charged, the reciprocating member 39 can reciprocate without applying damaging forces to the parts of the circuit breaker. When the breaker is tripped open and the closing latch structure 63 is then operated to close the breaker, the crank shaft 31 will be moved approximately 180 as the spring 53 discharges to close the breaker. This will move the missing-tooth portion 155 approximately 180 and away from the driving pawl 139. With the closing spring 53 discharged, the motor 113 is energized to operate the ratchet wheel 35 to charge the spring 53. Upon energization of the motor 113, the output shaft 115 thereof is rotated to move the roller 121 from the position seen in full lines in FIG. 6 throughthe positions seen in broken lines in FIG. 6 with the axis of the roller 121 moving in a circle as the output shaft 115 of the motor is rotated. During each revolution of the output shaft 115, the roller 121 is moved to operate against the plate 125 to drive the reciprocating member 39 in a counterclockwise (FIG. 4) direction during the first 180 of movement of the roller 121 during which movement the driving pawl 139 will advance the ratchet wheel 135 by one tooth.

During the second 180 of the full 360 movement of the roller 121, the holding pawl 149 (FIG. 4) will hold the ratchet wheel l35'in the advanced position and the reciprocating member 39, under the bias of the spring 131, will be returned clockwise to the lowermost position seen in FIG. 4. This sequence occurs during each revolution of the motor output shaft 115 until the rod 51 (FIG. 2) moves over center past the 180 position, whereupon the spring 53 will bias the rod 51 to the right (FIG. 2) tending to move the crank shaft 31 counterclockwise which movement is limited by the latch member 67 which engages the roller 45 on the crank arm 37 to latch the crank shaft 31 in the spring-charged position seen in FIG. 2. With the spring 53 in the charged position seen in FIG. 2, the ratchet wheel 35 is positioned such that the missing-tooth portion 155 thereof is opposite the driving pawl 139 so that upon continued rotation of the motor 114, as the motor slows to a stop, the reciprocating member 39 reciprocates harmlessly without applying damaging forces to the parts. The motor 1 13 may be automatically started and stopped by suitable limit switch means operated by the mechanism parts in a well-known manner. As can be understood with reference to FIG. 4, the arcuate surface 129 of the plate 125 permits the plate 125 to move across the face of the roller 219 as the reciprocating member 39 reciprocates against the roller.

' As was setforth above, rotation of the ratchet wheel 35 is produced by oscillation of the pawl 139 as a result of rotation of the motor crank 121 turning clockwise (FIG. 6), and the charging of the breaker closing spring 53 is achieved by counterclockwise rotation of the ratchet wheel 35. For that purpose, the motor 113 works only on the upstroke of the operating arm 119. On the downstroke thereof the motor idles as the pawl assembly is returned under action of the spring 131. During the working upstroke, the force delivered by the operating arm or the roller 121 at position 121a is at a minimum. Likewise, during the upstroke, the force delivered at the uppermost and lowermost positions of the crank or roller 121 is at a maximum (FIG. 9). During the upstroke, the roller 121 lifts the plate 125 from the lower (solid line) position to the upper (broken,

line) position as shown in FIG. 6.

Contrarily, when the operating arm 119 is on the downstroke, the bottom surface 129 moves downwardly from the broken line 129a position to the solid line position, resting on the surfaceof the roller 121 and in response to a force applied by the spring 131 (FIG. 4). During the downward stroke, the motor 113 idles because it is not applying any force to the reciprocating member 39. Indeed, the downward. pull of the tension spring 131 facilitates the downward movement.

Inorder to equalize the forces applied by the motor 113 to the operating arm 119 during the upward and downward strokes of the arm, a tension spring is attached to the assembly of the reciprocating member 39 and the operating arm 119 in accordance with this invention. In the embodiment shown in FIGS. 4, 5, and 6, the tension spring 165 is attached to the operating arm 119 with the lower end of the spring attached to a collar 167. The collar 167 is disposed between the roller 121 and the operating arm 119 and is rotatably mounted on a shaft 169 extending therebetween. The upper end of the spring 165 is attached to the supporting frame 111 at 171. Thus, during the downstroke of the operating arm 119, the tension spring 165 is extended. Subsequently, during the upstroke of the operating arm, the spring returns to its normal position and thereby applies an upward pull through the operating arm 119 to facilitate the motor 113 in lifting the reciprocating member 39.

For an analysis of the difference in the vertical force or torque required by the motor when the tension spring 165 is attached in the manner described, reference is made to FIG. 9. Four curves A, B, C, and D are shown in FIG. 9, wherein curve A is a torque produced by the motor only which is assumed constant, curve B is the torque produced by the spring only and is energy stored on the downward idle stroke, curve C is the vertical force of the crank pivot produced by the motor only, and curve D is the vertical force on the crank pivot produced by the spring only. The vertical difference (E) between the curves C and D at any given position of the crank movement is the increase in the vertical force provided by the spring. Thus, as the roller 121 moves from the lowermost (solid line) position (FIG. 6) to the 90 position 1210, the vertical force applied by the motor and spring is depicted in the curve D. As the operating arm 119'continues to move upwardly to the uppermost position 12lb of the roller, the spring 165 continues pulling the operating arm 1 19 upwardly.

As the operating arm 1 19 moves downwardly to its lowermost position, the tension spring 165 is extended during the downward idle stroke of the arm. When the operating arm has moved through one-half of its upward stroke (indicated by the roller position 121a), the motor torque is delivering its minimum upward force on the operating arm 119; however, the spring 165 is delivering its maximum force under the operating arm. One test has indicated that a large stalled torque motor which delivers 35 ft. pounds may be replaced by a small stalled torque motor which delivers only 25 ft. pounds where a suitable tension spring 165 is added in accordance with this invention.

Another embodiment of the invention is shown in FIG. 7 which includes the ratchet wheel 35, the reciprocating member 39, the pawl 139, and a motor 113a. In this embodiment, the position of the motor 113a differs from that of the motor 113 in FIG. 4 in that the motor 113a has an axis perpendicular to the plane of the ratchet wheel 35 rather than parallel thereto. Nevertheless, the teachings of the invention may be applied to the embodiment of FIG. 7 by providing a connecting link 173 between the operating arm 119 and the outer end of the reciprocating member 39. However, the tension spring 165 is preferably attached to the reciprocating member 39 rather than to the operating arm as shown in the embodiment of FIG. 4.

Still another embodiment of the invention is shown in FIG. 8 which likewise includes the ratchet wheel 35, the reciprocating arm 39, and the tension spring 165. In the embodiment of FIG. 8, the reciprocating arm 39 is provided with an elongated slot 175 to receive the outer end of the shaft 169. This embodiment is used as an alternative to that shown in FIG. 4 where it is preferred to delete the connecting link 173 as shown in FIG. 7.

Still another embodiment of the invention is shown in FIG. 4 in which a compression spring 177 is mounted below the shaft 169 and connected thereto by a collar 179. The lower end of the compression spring 177 is mounted upon a frame member 181. The compression spring 177 and the collar 179 may be substituted for the tension spring 165 and the collar 167. In the alternative, instead of using a tension spring 165 or a compression 177, a leaf-type spring may be provided.

In conclusion, it is shown that the downward idle stroke of the motor crank can be utilized to store energy in a spring which energy is released upon the upward-working stroke of the motor, thus assisting the motor to charge the circuit breaker closing spring. The addition of the so-called booster spring to the motor enables the closing spring of the circuit breaker to be charged at a much lower voltage, approximately -25 percent lower. For example, it was found that use of the spring enabled a heavy duty motor of 3000 amperes on a 50 Dl-IP350 type circuit breaker to be replaced with a standard motor. Moreover, by the addition of the spring, more powerful breaker closing springs can be charged without increasing the size of the motor, or lighter rated closing springs can be charged with smaller inexpensive motors. Finally, it is pointed out that the combination of themotor and the spring mechanism can be used in any structure where an oscillating member such as the reciprocating member 39 is involved and is not limited to circuit breaker devices.

What is claimed is:

1. A circuit breaker comprising a stationary contact, a movable contact, a crank shaft, a closing spring operatively connected to said crank shaft, a ratchet wheel on the crank shaft rotatable with the crank shaft, a reciprocating member having a pawl thereon and being supported to operate the pawl to advance the ratchet wheel upon reciprocation thereof, a motor comprising an output shaft, cam means on the output shaft operable upon rotation of the output shaft to operate the reciprocating member to advance the ratchet wheel to thereby charge the closing spring, the cam means being operable in directions toward and away from the reciprocating member, and spring means attached to one of the reciprocating members and output shaft for urging said member only in the direction of advancement of the ratchet wheel.

2. The circuit breaker of claim 1 in which the spring means is attached to the output shaft.

3. The circuit breaker of claim 2 in which the spring means comprises a tension spring on the side of the cam means corresponding to the reciprocation member.

4. The circuit breaker of claim 2 in which the spring means comprises a compression spring on the side of the cam means opposite that of the reciprocation member.

5. The circuit breaker of claim 1 in which the spring means is attached to the reciprocation member.

6. The circuit breaker of claim 5 in which the spring means comprises a tension spring on the side of the cam means corresponding to the direction of movement of the cam means toward the reciprocating member.

7. A stored energy mechanism for actuating a load between first and second positions comprising a crank shaft, a closing spring operatively connected to said crank shaft, a ratchet wheel on the crank shaft rotatable with the crank shaft, a reciprocating member having a pawl thereon and being supported to operate the pawl to advance the ratchet wheel upon reciprocation thereof, a motor comprising an output shaft, cam means on the output shaft operable upon rotation of the output shaft to operate the reciprocating member to advance the ratchet wheel to thereby charge the closing spring, the cam means being operable in directions toward and away from the reciprocating member, and spring means attached to one of the reciprocating members and output shaft for urging said member only in the direction of advancement of the ratchet wheel.

8. The mechanism of claim 7 in which the spring. 

1. A circuit breaker comprising a stationary contact, a movable contact, a crank shaft, a closing spring operatively connected to said crank shaft, a ratchet wheel on the crank shaft rotatable with the crank shaft, a reciprocating member having a pawl thereon and being supported to operate the pawl to advance the ratchet wheel upon reciprocation thereof, a motor comprising an output shaft, cam means on the output shaft operable upon rotation of the output shaft to operate the reciprocating member to advance the ratchet wheel to thereby charge the closing spring, the cam means being operable in directions toward and away from the reciprocating member, and spring means attached to one of the reciprocating members and output shaft for urging said member only in the direction of advancement of the ratchet wheel.
 2. The circuit breaker of claim 1 in which the spring means is attached to the output shaft.
 3. The circuit breaker of claim 2 in which the spring means comprises a tension spring on the side of the cam means corresponding to the reciprocation member.
 4. The circuit breaker of claim 2 in which the spring means comprises a compression spring on the side of the cam means opposite that of the reciprocation member.
 5. The circuit breaker of claim 1 in which the spring means is attached to the reciprocation member.
 6. The circuit breaker of claim 5 in which the spring means comprises a tension spring on the side of the cam means corresponding to the direction of movement of the cam means toward the reciprocating member.
 7. A stored energy mechanism for actuating a load between first and second positions comprising a crank shaft, a closing spring operatively connected to said crank shaft, a ratchet wheel on the crank shaft rotatable with the crank shaft, a reciprocating member having a pawl thereon and being supported to operate the pawl to advance the ratchet wheel upon reciprocation thereof, a motor comprising an output shaft, cam means on the output shaft operable upon rotation of the output shaft to operate the reciprocating member to advance the ratchet wheel to thereby charge the closing spring, the cam means being operable in directions toward and away from the reciprocating member, and spring means attached to one of the reciprocating members and output shaft for urging said member only in the direction of advancement of the ratchet wheel.
 8. The mechanism of claim 7 in which the spring means is attached to the output shaft.
 9. The mechanism of claim 7 in which the spring mEans is attached to the reciprocating member.
 10. The mechanism of claim 8 in which the spring means comprises a tension spring on the side of the cam means corresponding to the reciprocating member.
 11. The mechanism of claim 8 in which the spring means comprises a compression spring on the side of the cam means opposite that of the reciprocating member. 